|Location: La Robla, Spain|
Date: September 2021
Duration: 26 days
Material Demolished: 1,440 meters
Equipment: Aquajet Ergo, Hammelman high-pressure pump
During an annual maintenance shutdown, a cement plant in the village of La Robla, Spain, needed an effective way to repair a 100-meter-tall, 16-meter-diameter concrete silo used to store raw materials. Similar to many silos built in the 20th century, the walls of the concrete vessel were held together with rebar on the outer and inner layers of its concrete. But nothing was there to connect the two, and with age, it resulted in deteriorating and falling concrete.
In 2019, the cement plant hired a company specializing in concrete and structure repair to fix the silo. The hired crew used hand lances to remove the deteriorating concrete and scaled the silo with a scaffolding system to reach higher areas. Unfortunately, the crew was only able to repair the lower portion of the silo with the limited time they had, which put the remainder of the repair on hold.
When the project resumed two years later, Jose Rodriguez was hired to complete the repair. Rodriguez had been involved in the initial stage of repair and had since started another company, Fixen Structural Services, with a focus on structural reinforcements and repair. Fixen’s winning bid proposed using Aquajet’s Ergo Hydrodemolition robot to complete the challenging repair on budget and ahead of schedule.
Fixen Structural Services was established in 2019 to provide excellent structural repair and reinforcement for large structures, such as silos and bridges. The company, based in La Rinconada, Sevilla, Spain, works on projects across the globe. Fixen has a team of six, including two executive leaders, who are all skilled and trained in every service they provide.
“When we founded our company, we wanted to be grounded on the philosophy of performing the best quality repair we can,” said Rodriguez, chief operating officer of Fixen. “Although we have a small team, we are always excited to take on challenges — big or small — to expand our knowledge on our scope of work. We are open to trying new methods and equipment that can offer both power and simplicity to our projects in order to provide our customers with the best results possible.”
Fixen was introduced to Aquajet’s Ergo equipment in 2016, when Rodriguez attended World of Concrete in Las Vegas. He was astonished by its versatility and ability to successfully operate in confined spaces.
From his initial introduction to the Ergo, Rodriguez knew this piece of equipment would greatly benefit Fixen and its customers. Since the company invested in the Ergo in late 2020, the Fixen team has been thrilled with its quality, speed and accurate results. The equipment has proven to be a great replacement to hand lancing with its power and precision to complete repairs with limited work space. All in all, it has shown to be a more convenient, safe and cost-effective method.
“The Ergo has significantly improved our business,” Rodriguez said. “While it is compact and lightweight in design, it has all the power and versatility our crew needs for a variety of repair projects. We have been amazed with its results; it has become an essential piece of equipment for our company.”
The Ergo is a compact Hydrodemolition robot, with a climber that attaches to any standard scaffolding pipes and robotically moves along it, providing four times the power of a hand lance. Exerting 1,000 newtons of reaction force, the Ergo removes concrete or other material to a consistent preset depth. Its power, precision, speed and easy mobility make it ideal when working on vertical vessels and it is a favorite of employees who appreciate its ease of use. Fixen currently has two Ergos – one used as the primary machine and the other as a back-up unit.
The cement plant’s maintenance shutdown had a deadline of four weeks, so it was critical to complete repairs quickly. Because of his previous experience working on the silo and knowing the scope of the project, the plant managers approached Rodriguez and asked if Fixen could reinforce and repair the silo.
Although Fixen was one of many contractors who competed for the job, they were the only company that proposed a robotic Hydrodemolition method along with the use of hanging platforms to complete the work by the deadline.
“With traditional hand lancing for concrete repair, it would take a lot of time, up to 24 hours of non-stop work with a full crew of workers for four weeks or longer to complete a project. This is why the cement plant thought repairing the silo was an impossible task,” explained Rodriguez.
Fixen won the job by bringing an innovative solution that promised a repair that could be completed within four weeks. But if Fixen failed to meet the deadline, they would have to cover the remaining cost of finishing the project. The pressure was on to complete a successful structural repair, but their team had confidence they could complete the repairs on time using the Ergo.
The silo restoration job took place September 2021, two years after Rodriguez had worked on the first stages of the project with his former company.
The silo had a total of 32 sections to repair, each 45 meters long. The Fixen team connected the Ergo to an electrical hoist to reach the areas of repair. Fixen first used the Ergo to cut and remove the silo’s deteriorating concrete and then installed stirrups to anchor the existing horizontal rebars and attach them to the concrete. The final step of the repair was to fill the open spaces with fluid mortar to complete the section. Thanks to the Ergo, the team achieved a production rate of one meter per minute, removing two 45-meter vertical sections of concrete each day.
“Hydrodemolition with the Ergo really exceeded our expectations and allowed us to raise our standard in terms of planning, accuracy and performance optimization,” said Rodriguez. “It took more time to move the electric hoist than to remove the concrete.”
A crew of two removed a total of 1,440 meters of concrete and finished the job with two days to spare.
But with any job, there are challenges. With the silo’s height of 100 meters, rather than using a traditional scaffolding system, the Fixen team decided to opt for a much safer motorized hanging platform to comfortably stand on and bring additional equipment up with them as they worked on the structure.
Additionally, the Fixen crew needed approximately 100 meters of constant water pressure to ensure a successful Hydrodemolition repair. To achieve this, Fixen used a 2,500 bar Hammelman pump with a flow rate of 24 liters per minute. The pump, situated on the ground for the duration of the project, incorporated a 120 meter long, 3,000 bar pressure, hose extending up the structure to the Ergo. The Ergo controller was placed on a hanging platform, following the Ergo climber on each 4 meter vertical section. The cement plant provided the water and discarded the blast water into a cistern on-site.
Hydrodemolition contractors across the globe have the convenience of receiving training, consultations, machine parts and customer service from Aquajet distributors located in their region.
Fixen’s local Aquajet distributor is Hammelmann SL, a company Rodriguez has had a relationship with for about a decade.
“Since we started using Hydrodemolition for our projects, our team has worked with Aquajet for trainings on equipment, advancements and best practices,” Rodriguez said. “Having a direct relationship with our equipment manufacturer has been a great experience in the ways they have been so accommodating to help address our needs.”
Equipped with practical knowledge of Hydrodemolition and the Ergo, Fixen successfully repaired and completed a job that was once thought to be impossible.
“We are continuously surprised by the power and effectiveness of this machine when pursuing a variety of projects,” said Rodriguez. “We are proud to have given the cement plant a cost-effective and lasting solution to their operation.”
After a job well done, Fixen remains motivated to take on projects that allow them to use Aquajet’s innovative equipment to solve the most challenging situations.